On Fri, 4 Jan 2013 00:33:34 +0000 Ben Hutchings <[email protected]> wrote:
> From: Greg Rose <[email protected]> > > commit 115c9b81928360d769a76c632bae62d15206a94a upstream. > > Implement a new netlink attribute type IFLA_EXT_MASK. The mask > is a 32 bit value that can be used to indicate to the kernel that > certain extended ifinfo values are requested by the user application. > At this time the only mask value defined is RTEXT_FILTER_VF to > indicate that the user wants the ifinfo dump to send information > about the VFs belonging to the interface. > > This patch fixes a bug in which certain applications do not have > large enough buffers to accommodate the extra information returned > by the kernel with large numbers of SR-IOV virtual functions. > Those applications will not send the new netlink attribute with > the interface info dump request netlink messages so they will > not get unexpectedly large request buffers returned by the kernel. > > Modifies the rtnl_calcit function to traverse the list of net > devices and compute the minimum buffer size that can hold the > info dumps of all matching devices based upon the filter passed > in via the new netlink attribute filter mask. If no filter > mask is sent then the buffer allocation defaults to NLMSG_GOODSIZE. > > With this change it is possible to add yet to be defined netlink > attributes to the dump request which should make it fairly extensible > in the future. > > Signed-off-by: Greg Rose <[email protected]> > Signed-off-by: David S. Miller <[email protected]> > [bwh: Backported to 3.0: > - Adjust context > - Drop the change in do_setlink() that reverts commit f18da1456581 > ('net: RTNETLINK adjusting values of min_ifinfo_dump_size'), which > was never applied here] > Signed-off-by: Ben Hutchings <[email protected]> Not sure if these need my ack or not, nevertheless... Acked-by: Greg Rose <[email protected]) And thanks for doing this work Ben. - Greg > --- > include/linux/if_link.h | 1 + > include/linux/rtnetlink.h | 3 ++ > include/net/rtnetlink.h | 2 +- > net/core/rtnetlink.c | 77 > ++++++++++++++++++++++++++++++++++----------- 4 files changed, 63 > insertions(+), 20 deletions(-) > > diff --git a/include/linux/if_link.h b/include/linux/if_link.h > index 0ee969a..61a48b5 100644 > --- a/include/linux/if_link.h > +++ b/include/linux/if_link.h > @@ -137,6 +137,7 @@ enum { > IFLA_AF_SPEC, > IFLA_GROUP, /* Group the device belongs to */ > IFLA_NET_NS_FD, > + IFLA_EXT_MASK, /* Extended info mask, VFs, > etc */ __IFLA_MAX > }; > > diff --git a/include/linux/rtnetlink.h b/include/linux/rtnetlink.h > index bbad657..5415dfb 100644 > --- a/include/linux/rtnetlink.h > +++ b/include/linux/rtnetlink.h > @@ -600,6 +600,9 @@ struct tcamsg { > #define TCA_ACT_TAB 1 /* attr type must be >=1 */ > #define TCAA_MAX 1 > > +/* New extended info filters for IFLA_EXT_MASK */ > +#define RTEXT_FILTER_VF (1 << 0) > + > /* End of information exported to user level */ > > #ifdef __KERNEL__ > diff --git a/include/net/rtnetlink.h b/include/net/rtnetlink.h > index 678f1ff..3702939 100644 > --- a/include/net/rtnetlink.h > +++ b/include/net/rtnetlink.h > @@ -6,7 +6,7 @@ > > typedef int (*rtnl_doit_func)(struct sk_buff *, struct nlmsghdr *, > void *); typedef int (*rtnl_dumpit_func)(struct sk_buff *, struct > netlink_callback *); -typedef u16 (*rtnl_calcit_func)(struct sk_buff > *); +typedef u16 (*rtnl_calcit_func)(struct sk_buff *, struct > nlmsghdr *); > extern int __rtnl_register(int protocol, int msgtype, > rtnl_doit_func, rtnl_dumpit_func, > diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c > index 848de7b..e41ce2a 100644 > --- a/net/core/rtnetlink.c > +++ b/net/core/rtnetlink.c > @@ -60,7 +60,6 @@ struct rtnl_link { > }; > > static DEFINE_MUTEX(rtnl_mutex); > -static u16 min_ifinfo_dump_size; > > void rtnl_lock(void) > { > @@ -727,10 +726,11 @@ static void copy_rtnl_link_stats64(void *v, > const struct rtnl_link_stats64 *b) } > > /* All VF info */ > -static inline int rtnl_vfinfo_size(const struct net_device *dev) > +static inline int rtnl_vfinfo_size(const struct net_device *dev, > + u32 ext_filter_mask) > { > - if (dev->dev.parent && dev_is_pci(dev->dev.parent)) { > - > + if (dev->dev.parent && dev_is_pci(dev->dev.parent) && > + (ext_filter_mask & RTEXT_FILTER_VF)) { > int num_vfs = dev_num_vf(dev->dev.parent); > size_t size = nla_total_size(sizeof(struct nlattr)); > size += nla_total_size(num_vfs * sizeof(struct > nlattr)); @@ -768,7 +768,8 @@ static size_t rtnl_port_size(const > struct net_device *dev) return port_self_size; > } > > -static noinline size_t if_nlmsg_size(const struct net_device *dev) > +static noinline size_t if_nlmsg_size(const struct net_device *dev, > + u32 ext_filter_mask) > { > return NLMSG_ALIGN(sizeof(struct ifinfomsg)) > + nla_total_size(IFNAMSIZ) /* IFLA_IFNAME */ > @@ -786,8 +787,9 @@ static noinline size_t if_nlmsg_size(const struct > net_device *dev) > + nla_total_size(4) /* IFLA_MASTER */ > + nla_total_size(1) /* IFLA_OPERSTATE */ > + nla_total_size(1) /* IFLA_LINKMODE */ > - + nla_total_size(4) /* IFLA_NUM_VF */ > - + rtnl_vfinfo_size(dev) /* IFLA_VFINFO_LIST */ > + + nla_total_size(ext_filter_mask > + & RTEXT_FILTER_VF ? 4 : 0) /* > IFLA_NUM_VF */ > + + rtnl_vfinfo_size(dev, ext_filter_mask) /* > IFLA_VFINFO_LIST */ > + rtnl_port_size(dev) /* IFLA_VF_PORTS + > IFLA_PORT_SELF */ > + rtnl_link_get_size(dev) /* IFLA_LINKINFO */ > + rtnl_link_get_af_size(dev); /* IFLA_AF_SPEC */ > @@ -870,7 +872,7 @@ static int rtnl_port_fill(struct sk_buff *skb, > struct net_device *dev) > static int rtnl_fill_ifinfo(struct sk_buff *skb, struct net_device > *dev, int type, u32 pid, u32 seq, u32 change, > - unsigned int flags) > + unsigned int flags, u32 ext_filter_mask) > { > struct ifinfomsg *ifm; > struct nlmsghdr *nlh; > @@ -943,10 +945,11 @@ static int rtnl_fill_ifinfo(struct sk_buff > *skb, struct net_device *dev, goto nla_put_failure; > copy_rtnl_link_stats64(nla_data(attr), stats); > > - if (dev->dev.parent) > + if (dev->dev.parent && (ext_filter_mask & RTEXT_FILTER_VF)) > NLA_PUT_U32(skb, IFLA_NUM_VF, > dev_num_vf(dev->dev.parent)); > - if (dev->netdev_ops->ndo_get_vf_config && dev->dev.parent) { > + if (dev->netdev_ops->ndo_get_vf_config && dev->dev.parent > + && (ext_filter_mask & RTEXT_FILTER_VF)) { > int i; > > struct nlattr *vfinfo, *vf; > @@ -1033,11 +1036,20 @@ static int rtnl_dump_ifinfo(struct sk_buff > *skb, struct netlink_callback *cb) struct net_device *dev; > struct hlist_head *head; > struct hlist_node *node; > + struct nlattr *tb[IFLA_MAX+1]; > + u32 ext_filter_mask = 0; > > s_h = cb->args[0]; > s_idx = cb->args[1]; > > rcu_read_lock(); > + > + nlmsg_parse(cb->nlh, sizeof(struct rtgenmsg), tb, IFLA_MAX, > + ifla_policy); > + > + if (tb[IFLA_EXT_MASK]) > + ext_filter_mask = nla_get_u32(tb[IFLA_EXT_MASK]); > + > for (h = s_h; h < NETDEV_HASHENTRIES; h++, s_idx = 0) { > idx = 0; > head = &net->dev_index_head[h]; > @@ -1047,7 +1059,8 @@ static int rtnl_dump_ifinfo(struct sk_buff > *skb, struct netlink_callback *cb) if (rtnl_fill_ifinfo(skb, dev, > RTM_NEWLINK, NETLINK_CB(cb->skb).pid, > cb->nlh->nlmsg_seq, 0, > - NLM_F_MULTI) <= 0) > + NLM_F_MULTI, > + ext_filter_mask) <= 0) > goto out; > cont: > idx++; > @@ -1081,6 +1094,7 @@ const struct nla_policy ifla_policy[IFLA_MAX+1] > = { [IFLA_VF_PORTS] = { .type = NLA_NESTED }, > [IFLA_PORT_SELF] = { .type = NLA_NESTED }, > [IFLA_AF_SPEC] = { .type = NLA_NESTED }, > + [IFLA_EXT_MASK] = { .type = NLA_U32 }, > }; > EXPORT_SYMBOL(ifla_policy); > > @@ -1813,6 +1827,7 @@ static int rtnl_getlink(struct sk_buff *skb, > struct nlmsghdr* nlh, void *arg) struct net_device *dev = NULL; > struct sk_buff *nskb; > int err; > + u32 ext_filter_mask = 0; > > err = nlmsg_parse(nlh, sizeof(*ifm), tb, IFLA_MAX, > ifla_policy); if (err < 0) > @@ -1821,6 +1836,9 @@ static int rtnl_getlink(struct sk_buff *skb, > struct nlmsghdr* nlh, void *arg) if (tb[IFLA_IFNAME]) > nla_strlcpy(ifname, tb[IFLA_IFNAME], IFNAMSIZ); > > + if (tb[IFLA_EXT_MASK]) > + ext_filter_mask = nla_get_u32(tb[IFLA_EXT_MASK]); > + > ifm = nlmsg_data(nlh); > if (ifm->ifi_index > 0) > dev = __dev_get_by_index(net, ifm->ifi_index); > @@ -1832,12 +1850,12 @@ static int rtnl_getlink(struct sk_buff *skb, > struct nlmsghdr* nlh, void *arg) if (dev == NULL) > return -ENODEV; > > - nskb = nlmsg_new(if_nlmsg_size(dev), GFP_KERNEL); > + nskb = nlmsg_new(if_nlmsg_size(dev, ext_filter_mask), > GFP_KERNEL); if (nskb == NULL) > return -ENOBUFS; > > err = rtnl_fill_ifinfo(nskb, dev, RTM_NEWLINK, > NETLINK_CB(skb).pid, > - nlh->nlmsg_seq, 0, 0); > + nlh->nlmsg_seq, 0, 0, > ext_filter_mask); if (err < 0) { > /* -EMSGSIZE implies BUG in if_nlmsg_size */ > WARN_ON(err == -EMSGSIZE); > @@ -1848,8 +1866,31 @@ static int rtnl_getlink(struct sk_buff *skb, > struct nlmsghdr* nlh, void *arg) return err; > } > > -static u16 rtnl_calcit(struct sk_buff *skb) > +static u16 rtnl_calcit(struct sk_buff *skb, struct nlmsghdr *nlh) > { > + struct net *net = sock_net(skb->sk); > + struct net_device *dev; > + struct nlattr *tb[IFLA_MAX+1]; > + u32 ext_filter_mask = 0; > + u16 min_ifinfo_dump_size = 0; > + > + nlmsg_parse(nlh, sizeof(struct rtgenmsg), tb, IFLA_MAX, > ifla_policy); + > + if (tb[IFLA_EXT_MASK]) > + ext_filter_mask = nla_get_u32(tb[IFLA_EXT_MASK]); > + > + if (!ext_filter_mask) > + return NLMSG_GOODSIZE; > + /* > + * traverse the list of net devices and compute the minimum > + * buffer size based upon the filter mask. > + */ > + list_for_each_entry(dev, &net->dev_base_head, dev_list) { > + min_ifinfo_dump_size = max_t(u16, > min_ifinfo_dump_size, > + if_nlmsg_size(dev, > + > ext_filter_mask)); > + } > + > return min_ifinfo_dump_size; > } > > @@ -1884,13 +1925,11 @@ void rtmsg_ifinfo(int type, struct net_device > *dev, unsigned change) int err = -ENOBUFS; > size_t if_info_size; > > - skb = nlmsg_new((if_info_size = if_nlmsg_size(dev)), > GFP_KERNEL); > + skb = nlmsg_new((if_info_size = if_nlmsg_size(dev, 0)), > GFP_KERNEL); if (skb == NULL) > goto errout; > > - min_ifinfo_dump_size = max_t(u16, if_info_size, > min_ifinfo_dump_size); - > - err = rtnl_fill_ifinfo(skb, dev, type, 0, 0, change, 0); > + err = rtnl_fill_ifinfo(skb, dev, type, 0, 0, change, 0, 0); > if (err < 0) { > /* -EMSGSIZE implies BUG in if_nlmsg_size() */ > WARN_ON(err == -EMSGSIZE); > @@ -1948,7 +1987,7 @@ static int rtnetlink_rcv_msg(struct sk_buff > *skb, struct nlmsghdr *nlh) return -EOPNOTSUPP; > calcit = rtnl_get_calcit(family, type); > if (calcit) > - min_dump_alloc = calcit(skb); > + min_dump_alloc = calcit(skb, nlh); > > __rtnl_unlock(); > rtnl = net->rtnl; > > -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
